The present invention relates to intraocular lens combinations. More particularly, the invention relates to intraocular lens combinations which are adapted to provide substantial benefits, such as accommodating movement and/or inhibition of posterior capsule opacification (PCO) in the eye.
The human eye includes an anterior chamber between the cornea and iris, a posterior chamber including a capsular bag containing a crystalline lens, a ciliary muscle, a vitreous chamber behind the lens containing the vitreous humor, and a retina at the rear of this chamber. The human eye has a natural accommodation ability. The contraction and relaxation of the ciliary muscle provides the eye with near, intermediate and distant vision. This ciliary muscle action shapes the natural crystalline lens to the appropriate optical configuration for focusing light rays entering the eye on the retina.
After the natural crystalline lens is removed, for example, because of cataract or other condition, a conventional, monofocal IOL can be placed in the posterior chamber. Such a conventional IOL has very limited, if any, accommodating ability. However, the wearer of such an IOL continues to require the ability to view both near and far (distant) objects. Corrective spectacles may be employed as a useful solution. Recently, multifocal IOLs without accommodating movement have been used to provide near/far vision correction.
Attempts have been made to provide IOLs with accommodating movement along the optical axis of the eye as an alternative to shape changing. Examples of such attempts are set forth in Levy U.S. Pat. No. 4,409,691, U.S. Pat. Nos. 5,674,282 and 5,496,366 to Cumming, U.S. Pat. No. 6,176,878 to Gwon et al, U.S. Pat. No. 6,231,603 to Lang et al, and U.S. Pat. No. 6,406,494 to Laguette et al. The disclosure of each of these patents is incorporated herein by reference.
One problem that exists with such IOLs is that they often cannot move sufficiently to obtain the desired accommodation. The degree of accommodation has been closely related to the lens prescription of the individual patient. In addition, the presence of such lenses can result in cell growth from the capsular bag onto the optics of such lenses. Such cell growth, often referred to as posterior capsule opacification (PCO), can interfere with the clarity of the optic to the detriment of the lens wearer's vision.
It would be advantageous to provide IOLs adapted for accommodating movement, which can preferably achieve an acceptable amount of accommodation and/or a reduced risk of PCO.